.topSer {
    background-color: white;
}

.topSer a {
    color: #254375;
}

.allBack {
    width: 100%;
    background-image: url(https://zhang0228.oss-cn-wulanchabu.aliyuncs.com/beijing.jpg);
    background-repeat: no-repeat;
    background-size: 100% 5757px;
}
.main {
    position: relative;
    width: 3840px;
    height: 2455px;
    margin: auto;
}
.biaoqian{
    position: absolute;
    top: 75px;
    left: 160px;
    font-size: 40px;
}
.mainbox {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50% ,-50%);
    width: 2400px;
    height: 1500px;
    background-color: #f2f2fa;
}
.mainbox form {
    font-size: 80px;
}
.because{
    position: absolute;
    top: 90px;
    width: 800px;
    height: 100px;
    
    text-align: center;
    line-height: 100px;
}
.btnsure,
.btncsl {
    bottom: 80px;
    width: 430px;
    height: 160px;
    background-color: #e0e0e0;
    font-size: 80px;
    text-align: center;
    line-height: 160px;
    border-radius: 30px;
}
.btnsure {
    position: absolute;
    right: 490px;
}
.btncsl {
    position: absolute;
    right: 30px;
}
#text {
    position: absolute;
    bottom: 280px;
    left: 50%;
    transform: translateX(-50%);
    width: 2200px;
    height: 930px;
    font-size: 60px;
    background-color: #f2f2fa;
}
